It is impossible to have a mail account for an email address and not have a password. All Internet Service Providers and any other email provider eg: gmail will require everyone to use a username (which is usually the full email address) and a password to access an account. If she has forgotten her password to the mail account then the only place she can set a new password isin the webmail account accessed via a browser. There will be a 'forgotten password' or similar link when trying to access webmail account and she must follow the instructions to regain access to the account. Then she can set up a new password of her choice. In Thunderbird: If setting up a new > mail account Then use that newly created password. If account is already created and there is a need to update it: when prompted for a password, that newly created password is the one to use and remember to select the checkbox 'Remember Password' before clicking on OK. OR immediately update a stored password assuming the account is already created. * Settings > Privacy & Security * Scroll to Passwords section * Clickon 'Saved Passwords' * Click on 'Show Passwords' At this point she will be prompted for a password. IF she set up 'Primary Password' then it needs that password. Otherwise she will get a prompt from eg: Windows Security (I'm assuming she uses Windows OS) When she start up computer and gets asked for a password in order to access User Account - that is the password you enter. Look for the relevant lines for the account - mailbox://...for a pop account; imap://...for an imap account, smtp://....for the outgoing for account * Right click on each line in turn and selct 'Edit Password' * Completely clear contents and type in new password. If this is a gmail account it would be using oauth so remove all password lines for the account. Exit Thunderbird, allow background processes to complete. Restart Thunderbird. If this is gmail and you removed the oauth - when you restart Thunderbird, there will be a gmail prompt for password after which a prompt to allow Thunderbird access.